condition mean min max ZT0-3 9.599581 9.599581 9.599581 ZT4-7 12.713369499999999 12.713369499999999 12.713369499999999 ZT8-11 10.590833 10.590833 10.590833 ZT12-15 10.3808575 10.3808575 10.3808575 ZT16-19 11.5517685 11.5517685 11.5517685 ZT20-23 11.007052 11.007052 11.007052